Research On Long-distance And Smallgap Docking Technology Based On Visual Positioning

Docking assembly is one of the key links in the final assembly process of large equipment,aiming at the special situation of small gaps and large guiding strokes in the traditional large-scale equipment docking process,this article aims to adopt the technology based on visual positioning to realize the automatic docking process,with the actual engineering project as the research background,a long-distance and small-gap docking scheme based on vision positioning technology is designed under special circumstances.The main research content of the paper is as follows:(1)On the basis of in-depth understanding of visual positioning theory and proficiency in visual measurement methods,the design requirements,key issues and complex working conditions are coordinated,and the schematic diagram of the docking positioning system is established.The pose measurement is equivalent to the PnP problem and the non-coplanar two-dimensional vision problem,and the relationship between the pose transformation is analyzed.(2)Based on the summary and analysis of the targets used in recent experiments or in practice,the feature point coordinates of different feature graphics under perspective projection are calculated,and combined with the docking characteristics,an auxiliary target suitable for use in long distances and small gaps is designed.(3)For the obtained binarized target image,the existing Harris corner detection algorithm is improved,and the feature point recognition is approximated as the recognition of a rectangle,and a set of corner points that can form a unique rectangle is determined to be 4 for the subsequent P4P pose solution.For the obtained butt joint cross-sectional image,in view of the image blur problem caused by the camera lens depth of field,the fuzzy contrast enhancement algorithm is first used to increase the contrast of the image edge,and on this basis,the existing Canny operator was improved in a targeted manner.The least squares method is used to fit the straight line and the straight line represented by the partition and the edge of the gap is selected for the subsequent calculation of the dangerous distance.(4)On the basis of target design and image processing,the P4P attitude solution method is given,and the dangerous distance solution method is deduced.The dimensions between non-coplanar planes are combined with known conditions and converted to a unified reference for calculation,which solves the problem of ineffective calculation of dimensions in non-coplanar two-dimensional visual scenes.(5)Using the visual positioning idea of multiple measurements and multiple adjustments,a mathematical model of the distance between the side of the partition and the edge of the gap is established.Further,design error analysis experiments at different distances and different attitudes by simulating the on-site docking environment,and finally determine the pose adjustment method during the docking process.This article provides an effective docking positioning method for large-scale equipment long-distance and small-gap docking assembly,which is of great significance for ensuring the quality and reliability of docking components during the docking process and the safety of the production process.